Previously, the process that prevents us from seeing the visual environment moves when we turn or nod our head has been investigated by adapting subjects to conditions in which the environment moves in regular fashion dependent on the head movements. It has been shown that such adaptations consist of two components, a changed evaluation of eye movements and a changed evaluation of perceived visual direction at a level at which head position is taken into account. It has been found that the two component adaptations are measured by different tests. It is planned to find further specific tests and use all of them as information about the nature of the two kinds of adaptation and, thus, about the nature of the processes that keep the perceived environment stable when we move.